The present invention provides a means of improving the durability of a sensor, particularly a sensor which is attached with adhesive to the subject which is to be monitored. The preferred embodiment of the present invention is directed to improving the durability of sensors which are connected to pulse oximeters.
A pulse oximeter is a device which monitors the oxygen content of the blood of a subject by measuring the blood's absorption of light. The sensor includes a pair of light emitting diodes (L.E.D.) and a photocell detector which are coupled to wires connected to the pulse oximeter. The diodes, the detector, and a portion of the wires are covered with a flexible casing made of plastic and paper. An adhesive material is typically coupled to the casing.
When in use, the casing is wrapped around a part of the subject, typically a finger. When properly applied, the diodes are aligned on the subject so that they are facing the photocell detector with the subject's finger in between. The sensor is held in this position by affixing it to the skin with the adhesive material.
A known problem with the sensors described above is the limited lifespan of the adhesive and the lack of durability of the casing.
In addition, maintaining the cleanliness of the sensor is desirable since the casing touches the skin of the subject directly. However, the ability to clean the sensor is limited in that the adhesive portion of the sensor is permanently coupled to the casing. The adhesive portion cannot be conveniently cleaned without adversely affecting the strength of the remaining adhesive.
Another motivation for making such cleaning possible is to maintain the accuracy of the sensor. A study has shown that a build up of adhesive on the diodes may cause inaccurate readings by the pulse oximeter. Inaccurate readings on a medical instrument are clearly undesirable and potentially dangerous. The ability to clean the diodes and detector would provide a means to avoid this potential source of inaccuracy, potentially increasing patient safety.